Boiler generating steam according to the indirect method



May l9, 1931. R. UHDE 1,806,030

BOILER GENERATING STEAM ACCORDING TO THE INDIRECT METHOD Filed Oct. 27, 1928 Fig.1.

' Ana en tor.

Patented May 19, 1931 UNITED STATES PATENT OFFICE ROBERT UI-IDE, OF KASSEL-WILHELMSHOHE, GERMANY, ASIGNOR ,TO SCHMIDTSCHE HEISSDAMPF-GESELLSCHAFT MIT BESCI-IRANKTER HAFTUNG, 0F KASSEL-WIL- HELMSHOHE, GERMANY, A CORPORATION OF GERMANY JBOILER GENERATING- STEAM ACGORD'ING TO THE INDIRECT METHOD Application filed October 27, 1928, Serial No My invention relates to steam-boiler installations for the generation of high-pressure steam according to the indirect method in which the Working steam-boiler is heated by a heat carrier subjected to the heat of the furnace gases and circulating in a closed system.

In such steam-boiler installations, ithas been proposed to utilize the heat in the circulating heat carrier not only for the generation of high-pressure steam but also for heating the feed water for the working boiler.

In known steam boiler installations of this kind, the arrangement is such that the feedwater heater which is heated by the circulating heat carrier is disposed in series with the heating elements in the working boiler. In such a case, the preheating of the feed water is effected by the condensate of the heat-carrying steam after the latter has given up a large part of its heat in generating steam in the heating elements of the working boiler and has thereby been condensed.

In this series arrangement, the heat remaining in the condensate of the heat carrier is not suflicient to heat the feed water for the working steam boiler to the full temperature of evaporation; A part of the heat of the live heating steam must therefore be applied in the first place by way of the heating elements lying in the working steam boiler to bring the preheated feed water to the temperature of evaporation.

In contradistinction to the above, according to my present invention, the feed-water heater is not arranged in series with the heating elements in the working boiler but in parallel therewith, so that both the heating elements in the working boiler and also the heating coils or the like of the feed-water heater are heated by heat-carrier live steam.

As a result of such parallel connection, the heating elements have to transmit to the water in the boiler only the heat of evaporation while the preheating of the feed water up to the full temperature of evaporation is effected by the heating surface provided in the feed heater. v

In this way, the maintenance of the outside surface of the boiler heating elements in a 315,476, and in Germany November 14, 1927.

clean condition is considerably facilitated; since impurities that are precipitated at temperature below the temperature of evaporationare thrown down in the container of the feed heater in general in the form of a fine porous mud and do not come into contact with the surface of the heating elements.

A similar protection from deposits is at} fordedto the heating elements in connection with impurities which are carried over from a first preheating, for example in a flue-gas preheater, in a separated but not precipitated orm. Y

Such deposits can be readily removed from the container of the feed-water heater and its heating coils cleaned by jets of steam or water from the working boiler.

A further advantage of the parallel connection lies in the fact that on account of the smaller heating surface required for the working steam boiler, the thick-walled drum of the latte'r may .be smaller and its cost of production substantially reduced.

' In addition, as the preheating of the feed water to the temperature of evaporation is not efiected by progressive cooling-of the condensate but by condensing live steam of a temperature continuously maintained at a higher point, the mean temperature difference between the heat carrier and the feed water to be heated is correspondingly greater, and thereby also the quantity of heat transmitted, while in particular the co-efiicient of heat transmission of the condensing live steam is many times greater than of the cooling liquid condensate.

' In the accompanying diagrammatic drawings Fig. 1 shows a longitudinal section through one illustrative form of a steam boiler installation with parallel connection of the heating elements of the working steam boiler and of the feed-water heater according to my present invention. Fig. 2 shows a similar section through a slightly'modified form.

In Figure 1, the heat carrier is evaporated in the serpentines or coils,1, heated by the furnace gases, the steam so generated passing from the intermediate drum, 2, through the pipe, 3,'into a group of heating elements, 4:, lying in the water space of the working steam boiler, 5, the condensate from these heating elements flowing through the pipe, 6, into the water collector, 7.

According to the present invention, a part of the live heating steam passes from the pipe, 3, into the heating coils, 8, of the feedwater heater, 9, instead of into the heating elements, 4:, in. order "to heat the feedwater.

through the pipe, 15, into the working boiler, 5. V

In, Figure 2, the path of the live heating steam is the same asv in Figure 1, the only difference being that the condensate from the heating coils, 8, as well as, that from the heating elements, 4, is led into the common pipe, 16, which is connected to the water collector, 7 of the heat-carrier evaporating system.

The working steam generated passes, in a known manner through the pipe, ,17, into the superheater, 18, and thence through the pipe, 19, to the engine.

From the pipe, 17, the branch, 20, fitted with a shut-off valve, 21,:is led to the container of the feed-water heater, 9, to which is connected in addition the pipe, 22, also fitted with a shut-off valve, 23, so that by means of the branch pipe, anymud that has collected in the feed-heater container can be blown out as. required. I

In larger boiler units, more than one. feedwater heater may beprovided while in addition, instead of a single heating coil, a group ofhe-ating elements may be arranged the container of the feed-water heater.

I What I claim is:

1,111 a steam generator wherein high pressure steam is indirectly generated by means of a heat carrier passing through the heating elements of a working steam boiler and circulatingin a closed circuit a portion of which is heated by hot gases, and a feed-water heater having heating elements therein, said iecd-water heater heating elements and said heating elements of the working steam boiler being connected in parallel with respect to the heat carrier circuit.

2. In a steam-boiler installation for the generation of high-pressure steam according to the indirect method by means of a heat (121E116? circulation in a closed circuit and heated by the hot gases in the. evaporating system of the closed circuit, iii-combination a working boiler, heating elements lying in the water space of said boiler, a feed water heating elements lying in the water space of heater, heatingelements lying in said feedwater heater, a pipe connection between the heat carrier evaporating system and said boiler heating elements, and a pipe connection between the heat carrier eva orating system and said feed-water heating e ements, said pipe connections being disposed in parallel. r I 3. In a steam-boiler installation for the generation of high-pressurezsteam according to the indirect method by means of a heat carrier circulating in a closed circuit and heated by the hot gases in the evaporating system' of the'closed circuit, in combination a working boiler, heating elements lying in the water space of said boiler, afeed water heater, heating elements lyingin said feed water heater,-pipes connecting the upper part of the heat carrier evaporatingsystem with the heatingelements in the boiler and inthe feed water heater for leading heat-carrier live steam to said heating elements, said pipe connections being disposed in parallel and pipe connections between said heating elements. and the lowerpart of the heat-carrier evaporating system. for leading back the condensate of the heat-carrier steam.

g 4.. In a steam-boiler installation for the generation of high-pressure steam. according to the. indirect method by means of a heat carrier circulating in a closed circuit and heated by the hot gases, in the evaporating system of the closed-circuitin combination afworking boiler, heating elements lying in tions, between the heat-carrier evaporating system and said heating elements in. the boiler and the feed water heater, said pipe connections. being disposed in parallel, and a pipe connection between. the working boiler and the container of the feedwater heater.

5. In combination, a working steam boiler,

said steam. boiler, a feed-water heater, heating elements lying within said heater, a set of water tubes. constituting heat absorbing elements, upper and lower headers for said ,4,

tubes,-means,.for directly connecting one end 11 of the heating elements of theworking steam boiler and of thefeed-w-ater heater with said upper header, and means for connecting the other ends of said heating elements with said lower header. I

' 6.. In a steam generator wherein high pressure. steamis indirectly generated by means of a heatcarrier passingthrough the heating elements of a working steam. boiler and ,1

circulating in. a closed circuit apart of which i is heated'by hot gases, a feedewate'r heater having heating elements therein, the heating elements, of the feed'water. heater and of the workingisteamboilerbeing connected in parallel with respect to'the heat carrier circuit,

and means for conducting steam from the working boiler to the top of the water space within the feed-water heater, said feed-water heater being provided with an outlet communicating with the bottom of said water space.

In testimony whereof I have affixed my signature.

ROBERT UHDE. 

